I saw some reports in my Twitter timeline this morning, and it does indeed look like Apple updated iTunes Connect to allow app developers to generate 100 promo codes for each release. Previously, the limit was set to 50 codes per app release; for years, developers have been asking (among other things) to see an increase in the amount of promo codes they can use to gift their apps to members of the press, friends, or other users.

The news hasn't been confirmed on Apple's Developer News website yet, but screenshots of the new promo code count have been posted by various developers. Based on my tests in iTunes Connect, the limit for book publishers is still set to 50.